hey guys i have a '80'cc bicycle motor and was told by the police that i need to have my license and register the bike. so since i had to get my license anyways i just decided to buy a street bike. Anyways now i have this motor and want to build a custom rc car chassis and mount it on. My question is, what size sprocket would i need to use in back? the front sprocket i beleive is 10 teeth, and the tires are 7".i want a decent top speed and good torque. Thanks guys